Featured Research

from universities, journals, and other organizations

Anthropologists Find 4.5 Million-year-old Hominid Fossils In Ethiopia

Date:

January 21, 2005

Source:

Indiana University

Summary:

Scientists from Indiana University Bloomington and seven other institutions have unearthed skeletal fossils of a human ancestor believed to have lived about 4.5 million years ago. The fossils, described in this week's Nature (Jan. 20), will help scientists piece together the mysterious transformation of primitive chimp-like hominids into more human forms.

Share This

IU Bloomington paleoanthropologist Sileshi Semaw holds the fossil of a hominid mandible (lower jaw bone) believed to be about 4.5 million years old.

Credit: Photo by: Sileshi Semaw

BLOOMINGTON, Ind. -- Scientists from Indiana University Bloomington and seven other institutions have unearthed skeletal fossils of a human ancestor believed to have lived about 4.5 million years ago. The fossils, described in this week's Nature (Jan. 20), will help scientists piece together the mysterious transformation of primitive chimp-like hominids into more human forms.

Related Articles

The fossils were retrieved from the Gona Study Area in northern Ethiopia, only one of two sites to yield fossil remains of Ardipithecus ramidus.

"A few windows are now opening in Africa to glance into the fossil evidence on the earliest hominids," said IUB paleoanthropologist Sileshi Semaw, who led the research.

Semaw and colleagues also report new evidence that suggests the human ancestors lived in close quarters with a menagerie of antelope, rhinos, monkeys, giraffes and hippos in a northern Ethiopia that was far wetter than it is today. The environmental reconstructions suggest a mosaic of habitats, from woodlands to grasslands. Research is continuing at Gona to determine which habitats A. ramidus preferred.

"We now have more than 30 fossils from at least nine individuals dated between 4.3 and 4.5 million years old," said Semaw, Gona Palaeoanthropological Research Project director and Stone Age Institute research scientist. The Stone Age Institute, a new research center dedicated to the study of early human evolution and culture, is affiliated with Indiana University's CRAFT, the Center for Research into the Anthropological Foundations of Technology.

In their letter to Nature, Semaw and his coauthors describe parts of one upper and two lower jaw bones -- with teeth still intact -- several loose teeth, part of a toe bone and intact finger bones. The scientists believe the fossils belong to nine individuals of the species A. ramidus. The scientists used argon isotope dating of volcanic materials found in the vicinity of the fossils to estimate their age.

In the 11 years since the naming of A. ramidus by University of California Berkeley anthropologist Tim White and colleagues, only a handful of fossils from the species have been found, and only at two sites -- the Middle Awash and Gona, both in Ethiopia. Other fossils of slightly older age are known in Kenya and Chad. Anthropologists working in Ethiopia believe Ardipithecus is the first hominid genus -- that is, human ancestors who lived just after a split with the lineage that produced modern chimpanzees.

Despite the millions of years that separate us, modern humans have a few things in common with A. ramidus. Fossils from Gona and elsewhere suggest that the ancient hominid walked on two feet and had diamond-shaped upper canines, not the "v"-shaped ones chimps use to chomp. Outwardly, however, A. ramidus would appear a lot more chimpanzee-like than human.

Gona has turned out to be a productive dig site. In a Nature cover story (Jan. 23, 1997), Semaw and colleagues reported the oldest known stone tools used by ancestral humans. The Gona artifacts showed that as early as 2.5 million years ago, hominids were remarkably skilled toolmakers. Last month (December 2004), Semaw coauthored a paper in Geological Society of America Bulletin summarizing Gona's geological properties and the site's cornucopia of hominid fossils spanning several million years. (Science magazine gave the article an "Editor's Choice" nod.)

Scott Simpson (Case Western Reserve University School of Medicine and the Cleveland Museum of Natural History), Jay Quade (University of Arizona), Naomi Levin (University of Utah), Robert Butler (University of Portland), Paul Renne (Berkeley Geochronology Center and the University of California, Berkeley), William McIntosh (New Mexico Bureau of Geology and Mineral Resources and New Mexico Tech.), Manuel Dominguez-Rodrigo (Universidad Complutense de Madrid) and Michael Rogers (Southern Connecticut State University) also contributed to the report. It was funded by grants from the Leakey Foundation, the National Science Foundation, the National Geographic Society and the Stone Age Institute.

The authors thank Ethiopia's Authority for Research and Conservation of Cultural Heritage, the National Museum of Ethiopia, and the Ethiopian Ministry of Youth, Sports and Culture for providing permits for the ongoing work at the Gona dig site, and the Afar people for making the fieldwork a success.

More Fossils & Ruins News

Featured Research

Mar. 31, 2015  Scientists have uncovered the earliest fossilized evidence of an insect caring for its young. The findings push back the earliest direct evidence of insect brood care by more than 50 million years, ... full story

Mar. 31, 2015  Paleontologists have discovered two new species of Saurichthys. The ~242 million year old predatory fishes were found in the fossil Lagerstไtte Monte San Giorgio, in Ticino. They are distinct from ... full story

Mar. 31, 2015  In the 1990s the discovery of the oldest human made and completely preserved wooden hunting weapons made the Paleolithic excavation site in Schoningen internationally renowned. Contained within the ... full story

Mar. 30, 2015  A new study reports that marine ecosystems can take thousands, rather than hundreds, of years to recover from climate-related upheavals. The study's authors analyzed thousands of invertebrate fossils ... full story

Mar. 27, 2015  What do butterflies, spiders and lobsters have in common? They are all surviving relatives of a newly identified species called Yawunik kootenayi, a marine creature with two pairs of eyes and ... full story

Mar. 27, 2015  Scientists have produced a 3-D reconstruction of the remains of a two-year-old Neanderthal recovered from an excavation carried out back in the 1970s at La Ferrassie (Dordogne, France). The work ... full story

Mar. 26, 2015  New research harnessing fragmentary fossils suggests our genus has come in different shapes and sizes since its origins over two million years ago, and adds weight to the idea that humans began to ... full story

Mar. 25, 2015  New findings from an international team of archaeological researchers highlight the complexity of geopolitics in Aztec era Mesoamerica and illustrate how the relationships among ancient states ... full story

Mar. 24, 2015  A previously undiscovered species of crocodile-like amphibian that lived during the rise of dinosaurs was among Earth's top predators more than 200 million years ago, a study shows. Palaeontologists ... full story

Featured Videos

Ancient Egyptian Beer Making Vessels Discovered in Israel

AFP (Mar. 30, 2015)  Fragments of pottery used by Egyptians to make beer and dating back 5,000 years have been discovered on a building site in Tel Aviv, the Israeli Antiquities Authority said on Sunday. Duration: 00:51
Video provided by AFP

Related Stories

Mar. 9, 2015  Recently released research on human evolution has revealed that species of early human ancestors had significant differences in facial features. Now, scientists have found that these early human ... full story

Mar. 4, 2015  The earliest known record of the genus Homo -- the human genus -- represented by a lower jaw with teeth, recently found in the Afar region of Ethiopia, dates to between 2.8 and 2.75 million years ... full story

Oct. 21, 2013  The search for a common ancestor linking modern humans with the Neanderthals who lived in Europe thousands of years ago has been a compelling subject for research. But a new study suggests the quest ... full story

Sep. 8, 2011  An analysis of a skull from the most complete early hominid fossils ever found suggests the large, complex human brain may have evolved more rapidly and at a later time than some other human ... full story

Feb. 16, 2011  "Too simple" and "not so fast" suggest biological anthropologists about the origins of human ancestry. The anthropologists question the claims that several prominent fossil ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.